target/arm: Use CP_ACCESS_TRAP_EL1 for traps that are always to EL1

target/arm: Use CP_ACCESS_TRAP_EL1 for traps that are always to EL1

We currently use CP_ACCESS_TRAP in a number of access functions where
we know we're currently at EL0; in this case the "usual target EL"
is EL1, so CP_ACCESS_TRAP and CP_ACCESS_TRAP_EL1 behave the same.
Use CP_ACCESS_TRAP_EL1 to more closely match the pseudocode for
this sort of check.

Note that in the case of the access functions foc cacheop to
PoC or PoU, the code was correct but the comment was wrong:
SCTLR_EL1.UCI traps for DC CVAC, DC CIVAC, DC CVAP, DC CVADP,
DC CVAU and IC IVAU should be system access traps, not UNDEFs.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20250130182309.717346-11-peter.maydell@linaro.org